The present invention relates to a tartaric acid amide derivative which is capable of forming clathrate compounds with various organic compounds and to methods of forming such clathrate compounds, particularly with target compounds in the presence of a plurality of compounds.
The inventors have previously clarified that particular types of diamides serving as host molecules take in alcohols and phenols of wide range that serve as guest molecules to form crystals of clathrate compounds.
For example, as such diamide compounds, Japanese Patent Laid-Open Nos. 61-207363 and 61-271235 disclose fumaric acid amide and oxalic acid amide, Japanese Patent Laid-Open No. 61-271267 discloses benzenetricarboxylic acid amide and benzenetetracarboxylic acid amide, and Japanese Patent Laid-Open No. 62-123161 discloses phthalic acid amide, 1,2-cyclohexanedicarboxylic acid amide, .DELTA..sup.4 -cyclohexene-1,2-dicarboxylic acid amide, phenylmalonic acid amide and pyridinedicarboxylic acid amide.
However, each of these diamide compounds exhibits an excellent effect in terms of inclusion, but does not contain any asymmetric carbon atom in itself. Therefore, when these diamide compounds are used with racemic alcohols and phenols for forming clathrate compounds, the clathrate compounds formed have no optical activity. These diamide compounds therefore have no ability to optically resolve racemic modifications.
It is thought that an optically active diamide compound may be synthesized for the purpose of obtaining an optically active clathrate compound. However, this cannot be done easily.
It is well known that a compound which is synthesized by a chemical method alone is generally a racemic modification containing dextrorotatory and levorotatory components in equal quantities and is optically inactive. Since optical resolution is therefore necessary in order to obtain an optically active compound from such a compound, use of such a compound makes the method of obtaining an optically active compound troublesome and economically disadvantageous.
For example, the inventors disclose d- and l-propargyl alcohol derivatives serving as optically active host compounds and a method of producing these compounds in Japanese Patent Laid-Open No. 150526/1983. In other words, a class of propargyl alcohol having the structural formula described below combines with an alkaloid ((-brucine) in a natural form to form a complex, with an optically active clathrate compound in which propargyl alcohol serves as a host compound being crystallized as a result. ##STR2## From the so-formed clathrate compound, either a diastereomer of l-brucine and d-propargyl alcohol derivative or a diastereomer of l-brucine and l-propargyl alcohol derivative is crystallized by utilizing the difference in solubility of each according to the reaction conditions. Then, the crystallized diastereomer is decomposed by using an acid to isolate optically active propargyl alcohol derivative.
However, since this method requires the process of synthesizing a racemic modification of the host compound and the subsequent process of optically resolving the racemic modification, the method involves much labor and is troublesome.
The above is also the same with optically active amides which cannot be easily obtained by a method comprising chemical synthesis and optical resolution, and there is no method available which can be put into practical use.